[PATCH 3/3] clk: add clock lookup from devicetree
Lucas Stach
dev at lynxeye.de
Tue Jun 4 03:29:11 EDT 2013
Taken from the Linuxkernel with some small adjustments for barebox.
Signed-off-by: Lucas Stach <dev at lynxeye.de>
---
drivers/clk/clk.c | 97 ++++++++++++++++++++++++++++++++++++++++++++++++++++
drivers/clk/clkdev.c | 74 +++++++++++++++++++++++++++++++++++++++
include/linux/clk.h | 33 ++++++++++++++++++
3 files changed, 204 insertions(+)
diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c
index 690a0c6..bad3386 100644
--- a/drivers/clk/clk.c
+++ b/drivers/clk/clk.c
@@ -16,6 +16,7 @@
*/
#include <common.h>
#include <errno.h>
+#include <malloc.h>
#include <linux/clk.h>
#include <linux/err.h>
@@ -253,6 +254,102 @@ int clk_is_enabled_always(struct clk *clk)
return 1;
}
+#ifdef CONFIG_OFTREE
+/**
+ * struct of_clk_provider - Clock provider registration structure
+ * @link: Entry in global list of clock providers
+ * @node: Pointer to device tree node of clock provider
+ * @get: Get clock callback. Returns NULL or a struct clk for the
+ * given clock specifier
+ * @data: context pointer to be passed into @get callback
+ */
+struct of_clk_provider {
+ struct list_head link;
+
+ struct device_node *node;
+ struct clk *(*get)(struct of_phandle_args *clkspec, void *data);
+ void *data;
+};
+
+static LIST_HEAD(of_clk_providers);
+
+struct clk *of_clk_src_onecell_get(struct of_phandle_args *clkspec, void *data)
+{
+ struct clk_onecell_data *clk_data = data;
+ unsigned int idx = clkspec->args[0];
+
+ if (idx >= clk_data->clk_num) {
+ pr_err("%s: invalid clock index %d\n", __func__, idx);
+ return ERR_PTR(-EINVAL);
+ }
+
+ return clk_data->clks[idx];
+}
+EXPORT_SYMBOL_GPL(of_clk_src_onecell_get);
+
+/**
+ * of_clk_add_provider() - Register a clock provider for a node
+ * @np: Device node pointer associated with clock provider
+ * @clk_src_get: callback for decoding clock
+ * @data: context pointer for @clk_src_get callback.
+ */
+int of_clk_add_provider(struct device_node *np,
+ struct clk *(*clk_src_get)(struct of_phandle_args *clkspec,
+ void *data),
+ void *data)
+{
+ struct of_clk_provider *cp;
+
+ cp = kzalloc(sizeof(struct of_clk_provider), GFP_KERNEL);
+ if (!cp)
+ return -ENOMEM;
+
+ cp->node = np;
+ cp->data = data;
+ cp->get = clk_src_get;
+
+ list_add(&cp->link, &of_clk_providers);
+ pr_debug("Added clock from %s\n", np->full_name);
+
+ return 0;
+}
+EXPORT_SYMBOL_GPL(of_clk_add_provider);
+
+/**
+ * of_clk_del_provider() - Remove a previously registered clock provider
+ * @np: Device node pointer associated with clock provider
+ */
+void of_clk_del_provider(struct device_node *np)
+{
+ struct of_clk_provider *cp;
+
+ list_for_each_entry(cp, &of_clk_providers, link) {
+ if (cp->node == np) {
+ list_del(&cp->link);
+ kfree(cp);
+ break;
+ }
+ }
+}
+EXPORT_SYMBOL_GPL(of_clk_del_provider);
+
+struct clk *of_clk_get_from_provider(struct of_phandle_args *clkspec)
+{
+ struct of_clk_provider *provider;
+ struct clk *clk = ERR_PTR(-ENOENT);
+
+ /* Check if we have such a provider in our array */
+ list_for_each_entry(provider, &of_clk_providers, link) {
+ if (provider->node == clkspec->np)
+ clk = provider->get(clkspec, provider->data);
+ if (!IS_ERR(clk))
+ break;
+ }
+
+ return clk;
+}
+#endif
+
static void dump_one(struct clk *clk, int verbose, int indent)
{
struct clk *c;
diff --git a/drivers/clk/clkdev.c b/drivers/clk/clkdev.c
index 256927e..0b91af0 100644
--- a/drivers/clk/clkdev.c
+++ b/drivers/clk/clkdev.c
@@ -19,10 +19,80 @@
#include <linux/clkdev.h>
#include <init.h>
#include <malloc.h>
+#include <of.h>
#include <stdio.h>
static LIST_HEAD(clocks);
+#if defined(CONFIG_OFTREE) && defined(CONFIG_COMMON_CLK)
+struct clk *of_clk_get(struct device_node *np, int index)
+{
+ struct of_phandle_args clkspec;
+ struct clk *clk;
+ int rc;
+
+ if (index < 0)
+ return ERR_PTR(-EINVAL);
+
+ rc = of_parse_phandle_with_args(np, "clocks", "#clock-cells", index,
+ &clkspec);
+ if (rc)
+ return ERR_PTR(rc);
+
+ clk = of_clk_get_from_provider(&clkspec);
+ return clk;
+}
+EXPORT_SYMBOL(of_clk_get);
+
+/**
+ * of_clk_get_by_name() - Parse and lookup a clock referenced by a device node
+ * @np: pointer to clock consumer node
+ * @name: name of consumer's clock input, or NULL for the first clock reference
+ *
+ * This function parses the clocks and clock-names properties,
+ * and uses them to look up the struct clk from the registered list of clock
+ * providers.
+ */
+struct clk *of_clk_get_by_name(struct device_node *np, const char *name)
+{
+ struct clk *clk = ERR_PTR(-ENOENT);
+
+ /* Walk up the tree of devices looking for a clock that matches */
+ while (np) {
+ int index = 0;
+
+ /*
+ * For named clocks, first look up the name in the
+ * "clock-names" property. If it cannot be found, then
+ * index will be an error code, and of_clk_get() will fail.
+ */
+ if (name)
+ index = of_property_match_string(np, "clock-names",
+ name);
+ clk = of_clk_get(np, index);
+ if (!IS_ERR(clk))
+ break;
+ else if (name && index >= 0) {
+ pr_err("ERROR: could not get clock %s:%s(%i)\n",
+ np->full_name, name ? name : "", index);
+ return clk;
+ }
+
+ /*
+ * No matching clock found on this node. If the parent node
+ * has a "clock-ranges" property, then we can try one of its
+ * clocks.
+ */
+ np = np->parent;
+ if (np && !of_get_property(np, "clock-ranges", NULL))
+ break;
+ }
+
+ return clk;
+}
+EXPORT_SYMBOL(of_clk_get_by_name);
+#endif
+
/*
* Find the correct struct clk for the device and connection ID.
* We do slightly fuzzy matching here:
@@ -109,6 +179,10 @@ struct clk *clk_get(struct device_d *dev, const char *con_id)
if (!IS_ERR(clk))
return clk;
+ clk = of_clk_get_by_name(dev->device_node, con_id);
+ if (!IS_ERR(clk))
+ return clk;
+
return clk_get_sys(dev_id, con_id);
}
EXPORT_SYMBOL(clk_get);
diff --git a/include/linux/clk.h b/include/linux/clk.h
index 37a4813..0f7158a 100644
--- a/include/linux/clk.h
+++ b/include/linux/clk.h
@@ -11,6 +11,8 @@
#ifndef __LINUX_CLK_H
#define __LINUX_CLK_H
+#include <linux/err.h>
+
struct device_d;
/*
@@ -210,4 +212,35 @@ void clk_dump(int verbose);
#endif
+struct device_node;
+struct of_phandle_args;
+
+#if defined(CONFIG_OFTREE) && defined(CONFIG_COMMON_CLK)
+int of_clk_add_provider(struct device_node *np,
+ struct clk *(*clk_src_get)(struct of_phandle_args *args,
+ void *data),
+ void *data);
+void of_clk_del_provider(struct device_node *np);
+
+struct clk_onecell_data {
+ struct clk **clks;
+ unsigned int clk_num;
+};
+struct clk *of_clk_src_onecell_get(struct of_phandle_args *clkspec, void *data);
+
+struct clk *of_clk_get(struct device_node *np, int index);
+struct clk *of_clk_get_by_name(struct device_node *np, const char *name);
+struct clk *of_clk_get_from_provider(struct of_phandle_args *clkspec);
+#else
+static inline struct clk *of_clk_get(struct device_node *np, int index)
+{
+ return ERR_PTR(-ENOENT);
+}
+static inline struct clk *of_clk_get_by_name(struct device_node *np,
+ const char *name)
+{
+ return ERR_PTR(-ENOENT);
+}
+#endif
+
#endif
--
1.8.2.1
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